1. Field of the Invention
The present invention relates to a liquid-jet head which ejects jets of liquid, a method of manufacturing the same, and a liquid-jet apparatus. Particularly, the present invention relates to an ink-jet recording head, a method of manufacturing the same, and an ink-jet recording apparatus, in which the ink-jet recording head causes nozzle orifices to eject ink droplets by having piezoelectric elements pressurize ink supplied to pressure generating chambers communicating with the nozzle orifices.
2. Description of the Related Art
In an ink-jet recording head, a vibration plate constitutes part of pressure generating chambers communicating with nozzle orifices which eject ink droplets. Piezoelectric elements deform this vibration plate to pressurize ink in the pressure generating chambers, thereby causing the nozzle orifices to eject ink droplets. There are two types of piezoelectric actuators which have been employed by this ink-jet recording head for practical use: a piezoelectric actuator of a longitudinal vibration mode which extends and contracts in an axial direction of the piezoelectric elements, and a piezoelectric actuator of a flexure vibration mode.
A well-known example of the ink-jet recording head employing the actuator of the flexure vibration mode is as follows: a uniform piezoelectric material layer is formed over the entire surface of the vibration plate by deposition technology; this piezoelectric material layer is cut into pieces by use of a lithography method so that the shape thereof becomes suitable for the pressure generating chambers; and the piezoelectric elements are formed independently for the respective pressure generating chambers.
In addition, the following structure is generally employed by the ink-jet recording head. Pressure generating chambers and piezoelectric elements are formed on a passage-forming substrate, and a plate having a piezoelectric element holding portion is joined with the side of this passage-forming substrate where the piezoelectric elements are formed. A nozzle plate provided with nozzle orifices is joined with the side opposite the side where the piezoelectric elements are formed. By sealing the piezoelectric elements in the piezoelectric element holding portion, damage to the piezoelectric elements due to, for example, external environment such as atmospheric vapors is prevented (e.g., refer to Japanese Unexamined Patent Publication No. 2000-127379).
However, in the ink-jet recording head with this structure, the pressure generating chambers and the like are formed while the plate having the piezoelectric element holding portion is joined with the passage-forming substrate. Thereafter, the nozzle plate is joined with the passage-forming substrate. Thus, there is a problem that this is likely to cause connection defects of the nozzle plate. In other words, if the nozzle plate is joined with the passage-forming substrate as being pressured, the passage-forming substrate is deformed toward the piezoelectric element holding portion. Accordingly, a problem arises that the sufficient connection strength cannot be obtained. Note that this problem arises not only in the ink-jet recording head which ejects ink, but also in other liquid-jet heads which eject liquid other than ink.